After the latest update, the "Use column as molecule title" option in the SDF Writer node has changed. The drop-down list of column names only has one entry - "Row ID" - and none of the other columns in the input table are available for selection.
Thanks for reporting it. It will be fixed in KNIME 2.12.1.
We just released 2.12.1 and the option is now back in. Thank you again for reporting it.